When I was younger I would buy stuff on yahoo auctions or ebay and then sell it to the local pawn shops, almost always made a profit, either that or I'd buy stuff from pawn shop that looked new and sold on ebay.
I would be an umpire for little league baseball (150 dollars a game) during summer time as well.
If you can, mow lawns, do lawnwork or whatever, or if you're talented musically, you can go to a big city around you (depending if your parents are cool with it or not) and play music downtown.